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authorOleg Nesterov <oleg@redhat.com>2011-04-26 22:37:11 +0200
committerChris Metcalf <cmetcalf@tilera.com>2011-05-04 14:41:53 -0400
commitceca3c193e73bb409d093515fae9e5ef02ffa2de (patch)
treeb29f24fb0c280dd04bc4cdd0d68ffdec06e48ad7
parentdc0b124d8edc6c2f95fc3a689cd40ec05ad85108 (diff)
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tile: do_hardwall_trap: do not play with task->sighand
1. do_hardwall_trap() checks ->sighand != NULL and then takes ->siglock. This is unsafe even if the task can't run (I assume it is pinned to the same CPU), its parent can reap the task and set ->sighand = NULL right after this check. Even if the compiler dosn't read ->sighand twice and this memory can't to away __group_send_sig_info() is wrong after that. Use do_send_sig_info(). 2. Send SIGILL to the thread, not to the whole process. Unless it has the handler or blocked this kills the whole thread-group as before. IIUC, different threads can be bound to different rect's. 3. Check PF_EXITING instead of ->sighand. A zombie thread can go away but its ->sighand can be !NULL. Reported-by: Matt Fleming <matt@console-pimps.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
-rw-r--r--arch/tile/kernel/hardwall.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/tile/kernel/hardwall.c b/arch/tile/kernel/hardwall.c
index e910530..3bddef7 100644
--- a/arch/tile/kernel/hardwall.c
+++ b/arch/tile/kernel/hardwall.c
@@ -268,12 +268,10 @@ void __kprobes do_hardwall_trap(struct pt_regs* regs, int fault_num)
found_processes = 0;
list_for_each_entry(p, &rect->task_head, thread.hardwall_list) {
BUG_ON(p->thread.hardwall != rect);
- if (p->sighand) {
+ if (!(p->flags & PF_EXITING)) {
found_processes = 1;
pr_notice("hardwall: killing %d\n", p->pid);
- spin_lock(&p->sighand->siglock);
- __group_send_sig_info(info.si_signo, &info, p);
- spin_unlock(&p->sighand->siglock);
+ do_send_sig_info(info.si_signo, &info, p, false);
}
}
if (!found_processes)